Random access configuration

ABSTRACT

Apparatuses, methods, and systems are disclosed for random access configuration. One method includes receiving a first cell-defining synchronization signal block on a carrier. The method includes synchronizing to the first cell-defining synchronization signal block. The method includes receiving a first system information message associated with a first serving cell of the first cell-defining synchronization signal block. The first system information message includes a first random access channel configuration. The method includes receiving a bandwidth part configuration via a dedicated message from the first serving cell that indicates a bandwidth part configured with a second random access channel configuration. The method includes performing random access according to the second random access channel configuration in the bandwidth part of the first serving cell.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. Pat. ApplicationSerial No. 17/121,489 filed on Dec. 14, 2020, which is a continuationapplication of U.S. Pat. Application Serial No. 16/195,319 filed on Nov.19, 2018 (now U.S. Pat. No. 10,869,338 issued Dec. 15, 2020), whichclaims priority to U.S. Pat. Application Serial No. 62/588,348 entitled“RANDOM ACCESS AND MOBILITY HANDLING” and filed on Nov. 18, 2017 forHyejung Jung, all of which are incorporated herein by reference in theirentirety.

FIELD

The subject matter disclosed herein relates generally to wirelesscommunications and more particularly relates to random accessconfiguration.

BACKGROUND

The following abbreviations are herewith defined, at least some of whichare referred to within the following description: Third GenerationPartnership Project (“3GPP”), 5^(th) Generation (“5G”),Positive-Acknowledgment (“ACK”), Angle of Arrival (“AoA”), Angle ofDeparture (“AoD”), Additional MPR (“A-MPR”), Access Point (“AP”), BinaryPhase Shift Keying (“BPSK”), Buffer Status Report (“BSR”), Bandwidth(“BW”), Bandwidth Part (“BWP”), Carrier Aggregation (“CA”),Contention-Based Random Access (“CBRA”), Clear Channel Assessment(“CCA”), Cyclic Delay Diversity (“CDD”), Code Division Multiple Access(“CDMA”), Control Element (“CE”), Contention-Free Random Access(“CFRA”), Closed-Loop (“CL”), Coordinated Multipoint (“CoMP”), CyclicPrefix (“CP”), Cyclical Redundancy Check (“CRC”), Channel StateInformation (“CSI”), Common Search Space (“CSS”), Control Resource Set(“CORESET”), Discrete Fourier Transform Spread (“DFTS”), DownlinkControl Information (“DCI”), Downlink (“DL”), Demodulation ReferenceSignal (“DMRS”), Downlink Pilot Time Slot (“DwPTS”), Enhanced ClearChannel Assessment (“eCCA”), Enhanced Mobile Broadband (“eMBB”), EvolvedNode B (“eNB”), Effective Isotropic Radiated Power (“EIRP”), EuropeanTelecommunications Standards Institute (“ETSI”), Frame Based Equipment(“FBE”), Frequency Division Duplex (“FDD”), Frequency DivisionMultiplexing (“FDM”), Frequency Division Multiple Access (“FDMA”),Frequency Division Orthogonal Cover Code (“FD-OCC”), General PacketRadio Services (“GPRS”), Guard Period (“GP”), Global System for MobileCommunications (“GSM”), Hybrid Automatic Repeat Request (“HARQ”),Identity or Identifier (“ID”), International Mobile Telecommunications(“IMT”), Internet-of-Things (“IoT”), Layer 2 (“L2”), Licensed AssistedAccess (“LAA”), Load Based Equipment (“LBE”), Listen-Before-Talk(“LBT”), Logical Channel (“LCH”), Logical Channel Prioritization(“LCP”), Long Term Evolution (“LTE”), Multiple Access (“MA”), MediumAccess Control (“MAC”), Multimedia Broadcast Multicast Services(“MBMS”), Modulation Coding Scheme (“MCS”), Master Information Block(“MIB”), Machine Type Communication (“MTC”), massive MTC (“mMTC”),Multiple Input Multiple Output (“MIMO”), Maximum Power Reduction(“MPR”), Multi User Shared Access (“MUSA”), Narrowband (“NB”),Negative-Acknowledgment (“NACK”) or (“NAK”), Next Generation Node B(“gNB”), Network Entity (“NE”), Non-Orthogonal Multiple Access (“NOMA”),New Radio (“NR”), Orthogonal Frequency Division Multiplexing (“OFDM”),Open-Loop (“OL”), Other System Information (“OSI”), Power AngularSpectrum (“PAS”), Power Control (“PC”), Primary Cell (“PCell”), PhysicalCell ID (“PCID”), Physical Broadcast Channel (“PBCH”), Physical DownlinkControl Channel (“PDCCH”), Packet Data Convergence Protocol (“PDCP”),Physical Downlink Shared Channel (“PDSCH”), Pattern Division MultipleAccess (“PDMA”), Physical Hybrid ARQ Indicator Channel (“PHICH”), PowerHeadroom (“PH”), Power Headroom Report (“PHR”), Physical Layer (“PHY”),Physical Random Access Channel (“PRACH”), Physical Resource Block(“PRB”), Physical Uplink Control Channel (“PUCCH”), Physical UplinkShared Channel (“PUSCH”), Quasi Co-Located (“QCL”), Quality of Service(“QoS”), Quadrature Phase Shift Keying (“QPSK”), Radio Access Network(“RAN”), Radio Access Technology (“RAT”), Radio Resource Control(“RRC”), Random Access Procedure (“RACH”), Random Access Response(“RAR”), Radio Link Control (“RLC”), Radio Network Temporary Identifier(“RNTI”), Reference Signal (“RS”), Remaining Minimum System Information(“RMSI”), Resource Spread Multiple Access (“RSMA”), Reference SignalReceived Power (“RSRP”), Round Trip Time (“RTT”), Receive (“RX”), SparseCode Multiple Access (“SCMA”), Scheduling Request (“SR”), SoundingReference Signal (“SRS”), Single Carrier Frequency Division MultipleAccess (“SC-FDMA”), Secondary Cell (“SCell”), Shared Channel (“SCH”),Sub-carrier Spacing (“SCS”), Service Data Unit (“SDU”),Signal-to-Interference-Plus-Noise Ratio (“SINR”), System InformationBlock (“SIB”), Synchronization Signal (“SS”), Synchronization SignalBlock (“SSB”), Supplementary Uplink (“SUL”), Transport Block (“TB”),Transport Block Size (“TBS”), Time-Division Duplex (“TDD”), TimeDivision Multiplex (“TDM”), Time Division Orthogonal Cover Code(“TD-OCC”), Transmission Power Control (“TPC”), Transmission ReceptionPoint (“TRP”), Transmission Time Interval (“TTI”), Transmit (“TX”),Uplink Control Information (“UCI”), User Entity/Equipment (MobileTerminal) (“UE”), Uplink (“UL”), Universal Mobile TelecommunicationsSystem (“UMTS”), Uplink Pilot Time Slot (“UpPTS”), Ultra-reliability andLow-latency Communications (“URLLC”), and Worldwide Interoperability forMicrowave Access (“WiMAX”).

In certain wireless communications networks, a random access channelconfiguration may be used. In such networks, a device may not know whichconfiguration to use.

BRIEF SUMMARY

Methods for random access configuration are disclosed. Apparatuses andsystems also perform the functions of the apparatus. One embodiment ofan apparatus for wireless communication that includes a processor and amemory coupled with the processor. The memory includes instructionsexecutable by the processor to cause the apparatus to receive a systeminformation message associated with a synchronization signal block. Thesystem information message includes a first random access channelconfiguration, receive a radio resource control message indicating abandwidth part configuration comprising a bandwidth part configured inaccordance with a second random access channel configuration, andperform a contention-free random access procedure on the bandwidth partand based on the second random access channel configuration.

One method of wireless communication at a user equipment (UE) includesreceiving a system information message associated with a synchronizationsignal block, wherein the system information message comprises a firstrandom access channel configuration, receiving a radio resource controlmessage indicating a bandwidth part configuration comprising a bandwidthpart configured in accordance with a second random access channelconfiguration, and performing a contention-free random access procedureon the bandwidth part and based on the second random access channelconfiguration.

One apparatus for wireless communication includes a processor and amemory coupled with the processor, the memory comprising instructionsexecutable by the processor to cause the apparatus to: transmit a systeminformation message associated with a synchronization signal block. Thesystem information message includes a first random access channelconfiguration; transmit a radio resource control message indicating abandwidth part configuration comprising a bandwidth part configured inaccordance with a second random access channel configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the embodiments briefly described abovewill be rendered by reference to specific embodiments that areillustrated in the appended drawings. Understanding that these drawingsdepict only some embodiments and are not therefore to be considered tobe limiting of scope, the embodiments will be described and explainedwith additional specificity and detail through the use of theaccompanying drawings, in which:

FIG. 1 is a schematic block diagram illustrating one embodiment of awireless communication system for random access configuration;

FIG. 2 is a schematic block diagram illustrating one embodiment of anapparatus that may be used for random access configuration;

FIG. 3 is a schematic block diagram illustrating one embodiment of anapparatus that may be used for random access configuration;

FIG. 4 is a schematic block diagram illustrating one embodiment of asystem including multiple TRPs;

FIG. 5 is a schematic block diagram illustrating one embodiment of SSBtransmission in a system having multiple TRPs;

FIG. 6 is a schematic block diagram illustrating one embodiment of SSBtransmission and PRACH resource configurations in a system havingmultiple TRPs;

FIG. 7 is a flow chart diagram illustrating one embodiment of a methodfor random access channel configuration; and

FIG. 8 is a flow chart diagram illustrating another embodiment of amethod for random access channel configuration.

DETAILED DESCRIPTION

As will be appreciated by one skilled in the art, aspects of theembodiments may be embodied as a system, apparatus, method, or programproduct. Accordingly, embodiments may take the form of an entirelyhardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.” Furthermore,embodiments may take the form of a program product embodied in one ormore computer readable storage devices storing machine readable code,computer readable code, and/or program code, referred hereafter as code.The storage devices may be tangible, non-transitory, and/ornon-transmission. The storage devices may not embody signals. In acertain embodiment, the storage devices only employ signals foraccessing code.

Certain of the functional units described in this specification may belabeled as modules, in order to more particularly emphasize theirimplementation independence. For example, a module may be implemented asa hardware circuit comprising custom very-large-scale integration(“VLSI”) circuits or gate arrays, off-the-shelf semiconductors such aslogic chips, transistors, or other discrete components. A module mayalso be implemented in programmable hardware devices such as fieldprogrammable gate arrays, programmable array logic, programmable logicdevices or the like.

Modules may also be implemented in code and/or software for execution byvarious types of processors. An identified module of code may, forinstance, include one or more physical or logical blocks of executablecode which may, for instance, be organized as an object, procedure, orfunction. Nevertheless, the executables of an identified module need notbe physically located together, but may include disparate instructionsstored in different locations which, when joined logically together,include the module and achieve the stated purpose for the module.

Indeed, a module of code may be a single instruction, or manyinstructions, and may even be distributed over several different codesegments, among different programs, and across several memory devices.Similarly, operational data may be identified and illustrated hereinwithin modules, and may be embodied in any suitable form and organizedwithin any suitable type of data structure. The operational data may becollected as a single data set, or may be distributed over differentlocations including over different computer readable storage devices.Where a module or portions of a module are implemented in software, thesoftware portions are stored on one or more computer readable storagedevices.

Any combination of one or more computer readable medium may be utilized.The computer readable medium may be a computer readable storage medium.The computer readable storage medium may be a storage device storing thecode. The storage device may be, for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, holographic,micromechanical, or semiconductor system, apparatus, or device, or anysuitable combination of the foregoing.

More specific examples (a non-exhaustive list) of the storage devicewould include the following: an electrical connection having one or morewires, a portable computer diskette, a hard disk, a random access memory(“RAM”), a read-only memory (“ROM”), an erasable programmable read-onlymemory (“EPROM” or Flash memory), a portable compact disc read-onlymemory (“CD-ROM”), an optical storage device, a magnetic storage device,or any suitable combination of the foregoing. In the context of thisdocument, a computer readable storage medium may be any tangible mediumthat can contain, or store a program for use by or in connection with aninstruction execution system, apparatus, or device.

Code for carrying out operations for embodiments may be any number oflines and may be written in any combination of one or more programminglanguages including an object oriented programming language such asPython, Ruby, Java, Smalltalk, C++, or the like, and conventionalprocedural programming languages, such as the “C” programming language,or the like, and/or machine languages such as assembly languages. Thecode may execute entirely on the user’s computer, partly on the user’scomputer, as a stand-alone software package, partly on the user’scomputer and partly on a remote computer or entirely on the remotecomputer or server. In the latter scenario, the remote computer may beconnected to the user’s computer through any type of network, includinga local area network (“LAN”) or a wide area network (“WAN”), or theconnection may be made to an external computer (for example, through theInternet using an Internet Service Provider).

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment. Thus, appearances of the phrases“in one embodiment,” “in an embodiment,” and similar language throughoutthis specification may, but do not necessarily, all refer to the sameembodiment, but mean “one or more but not all embodiments” unlessexpressly specified otherwise. The terms “including,” “comprising,”“having,” and variations thereof mean “including but not limited to,”unless expressly specified otherwise. An enumerated listing of itemsdoes not imply that any or all of the items are mutually exclusive,unless expressly specified otherwise. The terms “a,” “an,” and “the”also refer to “one or more” unless expressly specified otherwise.

Furthermore, the described features, structures, or characteristics ofthe embodiments may be combined in any suitable manner. In the followingdescription, numerous specific details are provided, such as examples ofprogramming, software modules, user selections, network transactions,database queries, database structures, hardware modules, hardwarecircuits, hardware chips, etc., to provide a thorough understanding ofembodiments. One skilled in the relevant art will recognize, however,that embodiments may be practiced without one or more of the specificdetails, or with other methods, components, materials, and so forth. Inother instances, well-known structures, materials, or operations are notshown or described in detail to avoid obscuring aspects of anembodiment.

Aspects of the embodiments are described below with reference toschematic flowchart diagrams and/or schematic block diagrams of methods,apparatuses, systems, and program products according to embodiments. Itwill be understood that each block of the schematic flowchart diagramsand/or schematic block diagrams, and combinations of blocks in theschematic flowchart diagrams and/or schematic block diagrams, can beimplemented by code. The code may be provided to a processor of ageneral purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions/acts specified in the schematic flowchartdiagrams and/or schematic block diagrams block or blocks.

The code may also be stored in a storage device that can direct acomputer, other programmable data processing apparatus, or other devicesto function in a particular manner, such that the instructions stored inthe storage device produce an article of manufacture includinginstructions which implement the function/act specified in the schematicflowchart diagrams and/or schematic block diagrams block or blocks.

The code may also be loaded onto a computer, other programmable dataprocessing apparatus, or other devices to cause a series of operationalsteps to be performed on the computer, other programmable apparatus orother devices to produce a computer implemented process such that thecode which execute on the computer or other programmable apparatusprovide processes for implementing the functions/acts specified in theflowchart and/or block diagram block or blocks.

The schematic flowchart diagrams and/or schematic block diagrams in theFigures illustrate the architecture, functionality, and operation ofpossible implementations of apparatuses, systems, methods and programproducts according to various embodiments. In this regard, each block inthe schematic flowchart diagrams and/or schematic block diagrams mayrepresent a module, segment, or portion of code, which includes one ormore executable instructions of the code for implementing the specifiedlogical function(s).

It should also be noted that, in some alternative implementations, thefunctions noted in the block may occur out of the order noted in theFigures. For example, two blocks shown in succession may, in fact, beexecuted substantially concurrently, or the blocks may sometimes beexecuted in the reverse order, depending upon the functionalityinvolved. Other steps and methods may be conceived that are equivalentin function, logic, or effect to one or more blocks, or portionsthereof, of the illustrated Figures.

Although various arrow types and line types may be employed in theflowchart and/or block diagrams, they are understood not to limit thescope of the corresponding embodiments. Indeed, some arrows or otherconnectors may be used to indicate only the logical flow of the depictedembodiment. For instance, an arrow may indicate a waiting or monitoringperiod of unspecified duration between enumerated steps of the depictedembodiment. It will also be noted that each block of the block diagramsand/or flowchart diagrams, and combinations of blocks in the blockdiagrams and/or flowchart diagrams, can be implemented by specialpurpose hardware-based systems that perform the specified functions oracts, or combinations of special purpose hardware and code.

The description of elements in each figure may refer to elements ofproceeding figures. Like numbers refer to like elements in all figures,including alternate embodiments of like elements.

FIG. 1 depicts an embodiment of a wireless communication system 100 forrandom access configuration. In one embodiment, the wirelesscommunication system 100 includes remote units 102 and network units104. Even though a specific number of remote units 102 and network units104 are depicted in FIG. 1 , one of skill in the art will recognize thatany number of remote units 102 and network units 104 may be included inthe wireless communication system 100.

In one embodiment, the remote units 102 may include computing devices,such as desktop computers, laptop computers, personal digital assistants(“PDAs”), tablet computers, smart phones, smart televisions (e.g.,televisions connected to the Internet), set-top boxes, game consoles,security systems (including security cameras), vehicle on-boardcomputers, network devices (e.g., routers, switches, modems), aerialvehicles, drones, or the like. In some embodiments, the remote units 102include wearable devices, such as smart watches, fitness bands, opticalhead-mounted displays, or the like. Moreover, the remote units 102 maybe referred to as subscriber units, mobiles, mobile stations, users,terminals, mobile terminals, fixed terminals, subscriber stations, UE,user terminals, a device, or by other terminology used in the art. Theremote units 102 may communicate directly with one or more of thenetwork units 104 via UL communication signals.

The network units 104 may be distributed over a geographic region. Incertain embodiments, a network unit 104 may also be referred to as anaccess point, an access terminal, a base, a base station, a Node-B, aneNB, a gNB, a Home Node-B, a relay node, a device, a core network, anaerial server, a radio access node, an AP, NR, a network entity, or byany other terminology used in the art. The network units 104 aregenerally part of a radio access network that includes one or morecontrollers communicably coupled to one or more corresponding networkunits 104. The radio access network is generally communicably coupled toone or more core networks, which may be coupled to other networks, likethe Internet and public switched telephone networks, among othernetworks. These and other elements of radio access and core networks arenot illustrated but are well known generally by those having ordinaryskill in the art.

In one implementation, the wireless communication system 100 iscompliant with NR protocols standardized in 3GPP, wherein the networkunit 104 transmits using an OFDM modulation scheme on the DL and theremote units 102 transmit on the UL using a SC-FDMA scheme or an OFDMscheme. More generally, however, the wireless communication system 100may implement some other open or proprietary communication protocol, forexample, WiMAX, IEEE 802.11 variants, GSM, GPRS, UMTS, LTE variants,CDMA2000, Bluetooth®, ZigBee, Sigfoxx, among other protocols. Thepresent disclosure is not intended to be limited to the implementationof any particular wireless communication system architecture orprotocol.

The network units 104 may serve a number of remote units 102 within aserving area, for example, a cell or a cell sector via a wirelesscommunication link. The network units 104 transmit DL communicationsignals to serve the remote units 102 in the time, frequency, and/orspatial domain.

In one embodiment, a remote unit 102 may receive a first cell-definingsynchronization signal block on a carrier. In some embodiments, theremote unit 102 may synchronize to the first cell-definingsynchronization signal block. In certain embodiments, the remote unit102 may receive a first system information message associated with afirst serving cell of the first cell-defining synchronization signalblock. In such embodiments, the first system information messageincludes a first random access channel configuration. In variousembodiments, the remote unit 102 may receive a bandwidth partconfiguration via a dedicated message from the first serving cell thatindicates a bandwidth part configured with a second random accesschannel configuration. In one embodiment, the remote unit 102 mayperform random access according to the second random access channelconfiguration in the bandwidth part of the first serving cell.Accordingly, the remote unit 102 may be used for random accessconfiguration.

In certain embodiments, a network unit 104 may transmit a firstcell-defining synchronization signal block on a carrier. In someembodiments, the network unit 104 may transmit a first systeminformation message associated with a first serving cell of the firstcell-defining synchronization signal block. In such embodiments, thefirst system information message includes a first random access channelconfiguration. In certain embodiments, the network unit 104 may transmita bandwidth part configuration via a dedicated message from the firstserving cell that indicates a bandwidth part configured with a secondrandom access channel configuration. In such embodiments, random accessis performed according to the second random access channel configurationin the bandwidth part of the first serving cell. Accordingly, thenetwork unit 104 may be used for random access configuration.

FIG. 2 depicts one embodiment of an apparatus 200 that may be used forrandom access configuration. The apparatus 200 includes one embodimentof the remote unit 102. Furthermore, the remote unit 102 may include aprocessor 202, a memory 204, an input device 206, a display 208, atransmitter 210, and a receiver 212. In some embodiments, the inputdevice 206 and the display 208 are combined into a single device, suchas a touchscreen. In certain embodiments, the remote unit 102 may notinclude any input device 206 and/or display 208. In various embodiments,the remote unit 102 may include one or more of the processor 202, thememory 204, the transmitter 210, and the receiver 212, and may notinclude the input device 206 and/or the display 208.

The processor 202, in one embodiment, may include any known controllercapable of executing computer-readable instructions and/or capable ofperforming logical operations. For example, the processor 202 may be amicrocontroller, a microprocessor, a central processing unit (“CPU”), agraphics processing unit (“GPU”), an auxiliary processing unit, a fieldprogrammable gate array (“FPGA”), or similar programmable controller. Insome embodiments, the processor 202 executes instructions stored in thememory 204 to perform the methods and routines described herein. Invarious embodiments, the processor 202 may: synchronize to a firstcell-defining synchronization signal block; and perform random accessaccording to a second random access channel configuration in a bandwidthpart of a first serving cell. The processor 202 is communicativelycoupled to the memory 204, the input device 206, the display 208, thetransmitter 210, and the receiver 212.

The memory 204, in one embodiment, is a computer readable storagemedium. In some embodiments, the memory 204 includes volatile computerstorage media. For example, the memory 204 may include a RAM, includingdynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and/or staticRAM (“SRAM”). In some embodiments, the memory 204 includes non-volatilecomputer storage media. For example, the memory 204 may include a harddisk drive, a flash memory, or any other suitable non-volatile computerstorage device. In some embodiments, the memory 204 includes bothvolatile and non-volatile computer storage media. In some embodiments,the memory 204 also stores program code and related data, such as anoperating system or other controller algorithms operating on the remoteunit 102.

The input device 206, in one embodiment, may include any known computerinput device including a touch panel, a button, a keyboard, a stylus, amicrophone, or the like. In some embodiments, the input device 206 maybe integrated with the display 208, for example, as a touchscreen orsimilar touch-sensitive display. In some embodiments, the input device206 includes a touchscreen such that text may be input using a virtualkeyboard displayed on the touchscreen and/or by handwriting on thetouchscreen. In some embodiments, the input device 206 includes two ormore different devices, such as a keyboard and a touch panel.

The display 208, in one embodiment, may include any known electronicallycontrollable display or display device. The display 208 may be designedto output visual, audible, and/or haptic signals. In some embodiments,the display 208 includes an electronic display capable of outputtingvisual data to a user. For example, the display 208 may include, but isnot limited to, an LCD display, an LED display, an OLED display, aprojector, or similar display device capable of outputting images, text,or the like to a user. As another, non-limiting, example, the display208 may include a wearable display such as a smart watch, smart glasses,a heads-up display, or the like. Further, the display 208 may be acomponent of a smart phone, a personal digital assistant, a television,a table computer, a notebook (laptop) computer, a personal computer, avehicle dashboard, or the like.

In certain embodiments, the display 208 includes one or more speakersfor producing sound. For example, the display 208 may produce an audiblealert or notification (e.g., a beep or chime). In some embodiments, thedisplay 208 includes one or more haptic devices for producingvibrations, motion, or other haptic feedback. In some embodiments, allor portions of the display 208 may be integrated with the input device206. For example, the input device 206 and display 208 may form atouchscreen or similar touch-sensitive display. In other embodiments,the display 208 may be located near the input device 206.

The transmitter 210 is used to provide UL communication signals to thenetwork unit 104 and the receiver 212 is used to receive DLcommunication signals from the network unit 104, as described herein. Insome embodiments, the receiver 212: receives a first cell-definingsynchronization signal block on a carrier; receives a first systeminformation message associated with a first serving cell of the firstcell-defining synchronization signal block, wherein the first systeminformation message includes a first random access channelconfiguration; and receives a bandwidth part configuration via adedicated message from the first serving cell that indicates a bandwidthpart configured with a second random access channel configuration.Although only one transmitter 210 and one receiver 212 are illustrated,the remote unit 102 may have any suitable number of transmitters 210 andreceivers 212. The transmitter 210 and the receiver 212 may be anysuitable type of transmitters and receivers. In one embodiment, thetransmitter 210 and the receiver 212 may be part of a transceiver.

FIG. 3 depicts one embodiment of an apparatus 300 that may be used forrandom access configuration. The apparatus 300 includes one embodimentof the network unit 104. Furthermore, the network unit 104 may include aprocessor 302, a memory 304, an input device 306, a display 308, atransmitter 310, and a receiver 312. As may be appreciated, theprocessor 302, the memory 304, the input device 306, the display 308,the transmitter 310, and the receiver 312 may be substantially similarto the processor 202, the memory 204, the input device 206, the display208, the transmitter 210, and the receiver 212 of the remote unit 102,respectively.

In certain embodiments, the transmitter 310: transmits a firstcell-defining synchronization signal block on a carrier; transmits afirst system information message associated with a first serving cell ofthe first cell-defining synchronization signal block, wherein the firstsystem information message includes a first random access channelconfiguration; and transmits a bandwidth part configuration via adedicated message from the first serving cell that indicates a bandwidthpart configured with a second random access channel configuration,wherein random access is performed according to the second random accesschannel configuration in the bandwidth part of the first serving cell.

Although only one transmitter 310 and one receiver 312 are illustrated,the network unit 104 may have any suitable number of transmitters 310and receivers 312. The transmitter 310 and the receiver 312 may be anysuitable type of transmitters and receivers. In one embodiment, thetransmitter 310 and the receiver 312 may be part of a transceiver.

In some embodiments, a BWP may include a group of contiguous PRBs tosupport reduced UE BW capability, UE BW adaptation, FDM of multiplenumerologies, and/or use of a non-contiguous spectrum. In certainembodiments, a connected mode UE may be UE-specifically and/orsemi-statically configured with one or more BWPs for a single carrier.In various embodiments, a bandwidth of a BWP may be less than or equalto a maximum UE bandwidth capability, but may be at least as large as abandwidth of an SSB. In such embodiments, the SSB may include primarysynchronization signals, secondary synchronization signals, and/or PBCH.In one embodiment, different UEs′ BWPs may fully or partially overlap,and it may be up to an NE (e.g., gNB) to coordinate scheduling ofdifferent UEs′ BWPs. In some embodiments, configuration parameters of aBWP may include a numerology (e.g., subcarrier spacing), a frequencylocation (e.g., center frequency), and/or a bandwidth (e.g., number ofPRBs). In certain embodiments, a given BWP may or may not contain anSSB.

In various embodiments, multiple SSBs may be transmitted within abandwidth of a carrier. However, in such embodiments, from a UEperspective, a cell may be associated with a single SSB in the frequencydomain, and a cell-defining SSB may have one or more associatedessential SIBs. The one or more associated essential SIBs may includeRMSI (e.g., system information not included in a MIB but essential foraccessing a cell). In some embodiments, a cell-defining SSB may be usedfor common PRB indexing and/or scrambling.

In certain embodiments, various methods may be used to perform randomaccess within a wideband carrier. In such embodiments, the widebandcarrier may refer to a carrier that includes one or more cell-definingSSBs. In some embodiments, various methods may be used to handle UEmobility if a UE changes to a different cell-defining SSB within awideband carrier.

As used herein, an initial active BWP may be defined by a frequencylocation, a bandwidth of an RMSI CORESET (e.g., the CORESET in which aPDCCH scheduling a PDSCH carrying the RMSI is transmitted), and/or anumerology of RMSI (e.g., subcarrier spacing and a CP length of a PDCCHscheduling RMSI and a PDSCH carrying RMSI). In various embodiments, aPDSCH delivering RMSI may be confined within an initial active DL BWP.

Moreover, as used herein, an initial active UP BWP may be defined as aBWP in which a UE performs a random access procedure includingtransmission of one or more random access preambles, a PUSCH for message3 (e.g., Msg.3), and/or a PUCCH for message 4 (e.g., Msg.4) HARQfeedback during an initial cell selection procedure. In certainembodiments, at least one initial active UL BWP configured percell-defining SSB is supported from a UE’s perspective. As used herein,a cell-defining SSB may be an SSB that corresponds to a specific celland provides information related to delivery of one or more essentialSIBs associated with the specific cell. Furthermore, a non-cell definingSSB may be an SSB that is associated with a specific cell but does notprovide information related to delivery of one or more essential SIBsassociated with the specific cell. In some embodiments, if a SUL isconfigured, an additional initial active UL BWP for SUL may beindependently configured.

In various embodiments, a default DL BWP of a PCell may be defined as aDL bandwidth part for which a UE performs measurement on a servingcell-defining SSB (e.g., an SSB corresponding to a serving cell) andmonitors common DCI (e.g., scheduling information of PDSCH carrying oneor more SIBs). In certain embodiments, if a default DL BWP is notconfigured, the default DL BWP may be an initial active DL BWP. In someembodiments, a UE may switch its active DL BWP to a default DL BWP if atimer expires. In such embodiments, the UE may start the timer at a timein which the UE switches its active DL BWP to a DL BWP other than thedefault DL BWP and the timer may be started at an initial value at eachinstance that it successfully decodes a PDCCH to schedule one or morePDSCHs in its active DL BWP.

In one embodiment, a UE may receive RMSI of a serving cell-defining SSBof a wideband carrier. In such an embodiment, the RMSI of the servingcell-defining SSB may include one or more RACH configurations.Furthermore, in such an embodiment, each of the one or more RACHconfigurations may be associated with each of one or more cell-definingSSBs of the wideband carrier. Moreover, in such an embodiment, the oneor more cell-defining SSBs of the wideband carrier may be transmitted ondifferent synchronization signal frequencies within the wideband carrier(e.g., by one or more cooperating TRPs). In some embodiments, the one ormore cooperating TRPs may be connected via an ideal or fiber backhauland/or controlled by a common scheduling unit or a common network entity(e.g., a base station, eNB, gNB). In certain embodiments, a RACHconfiguration included in RMSI of a serving cell-defining SSB may beassociated with more than one cell-defining SSBs of a wideband carrier(e.g., the serving cell-defining SSB, and another cell-defining SSB).

In various embodiments, a RACH configuration may include a PRACHconfiguration index indicating a PRACH format (e.g., defining a cyclicprefix length, a guard time duration, a preamble sequence length, and/ora number of preamble sequences), a time resource for RACH, a frequencyresource for RACH, a high speed flag, a root sequence index, a preambleinitial received target power, a zero correlation zone configuration(e.g., together with the high speed flag defining a set of allowedcyclic shifts for a root sequence), a waveform of message 3, asubcarrier spacing of message 3, an RSRP threshold for an SSB (e.g., toselect a serving SSB), a preamble power ramping step size, aMAC-contention resolution timer, and/or a random access response windowsize. In one embodiment, some information elements of one or more RACHconfigurations may be common, and the common information elements may besignaled only once without duplication in a given RMSI payload. Inanother embodiment, one or more RACH configurations may be separatelyand independently configured and/or signaled. In certain embodiments, anetwork entity (e.g., gNB) may explicitly and/or implicitly indicate toa UE whether a RACH configuration of the one or more RACH configurations(e.g., which is associated with a non-serving cell-defining SSBs of theone or more cell-defining SSBs of a wideband carrier) may be used forCBRA. In such embodiments, if CBRA is not allowed for the UE or CBRA isallowed but not signaled, the UE may assume (or have a default setting)that a RACH configuration associated with a non-serving cell-definingSSB may only be used for CFRA. In various embodiments, informationelements of some RACH configurations (e.g., all but one RACHconfiguration that is associated with a serving cell-defining SSB) maybe signaled in system information other than RMSI (e.g., OSI). Incertain embodiments, the system information other than RMSI may besignaled independently from the RMSI.

In some embodiments, RMSI of a serving cell-defining SSB may onlyinclude a RACH configuration associated with the serving cell-definingSSB. In such an embodiment, a UE may only use the RACH configuration ofthe serving cell-defining SSB for initial access (e.g., initial cellselection). Moreover, after the UE connects to a cell, the UE mayreceive other RACH configurations associated with non-servingcell-defining SSBs of one or more cell-defining SSBs of a widebandcarrier via dedicated RRC signaling. These dedicated RACH configurationsmay be included as a part of BWP configuration signaling. In certainembodiments, if a UE is configured with a particular DL/UL BWP viadedicated RRC signaling, the UE may be informed of a RACH configurationassociated with a non-serving cell-defining SSB of one or morecell-defining SSBs of a wideband carrier. In such embodiments, thenon-serving cell-defining SSB may be transmitted by a TRP that is thesame as or different from the TRP transmitting the serving cell-definingSSB and the non-serving cell-defining SSB may be transmitted within aparticular DL BWP. In such embodiments, RACH time and/or frequencyresources of a RACH configuration may exist within a particular UL BWP.

In one embodiment, a UE may receive an indication of a timing, afrequency, a DL path loss reference SSB, and/or a reference DL referencesignal (e.g., CSI-RS) for a dedicated RACH configuration. In someembodiments, even though a dedicated RACH configuration may beassociated with a non-serving cell-defining SSB, a gNB may indicate aserving cell-defining SSB as a timing, a frequency, and/or DL path lossreference SSB. In such embodiments, a serving cell-defining SSB and/ornon-serving cell-defining SSB may be quasi-co-located. In variousembodiments, one or more RACH preambles that a UE sends based on adedicated RACH configuration may be intended for a TRP transmitting aserving cell-defining SSB and/or monitored by the TRP transmitting theserving cell-defining SSB. In such embodiments, only contention-freerandom access may be allowed to avoid confusion between two TRPs. Insome embodiments, based on a received indication, a UE may: obtain DLtiming and/or DL path loss estimates and/or perform random accessaccording to a dedicated RACH configuration.

In certain embodiments, a gNB may indicate whether a UE can performcontention-based random access for a dedicated RACH configuration. Insuch embodiments, if not indicated, the UE may assume by default thatthe dedicated RACH configuration is used only for contention-free randomaccess. In some embodiments, if a gNB indicates quasi-co-locationbetween a serving cell-defining SSB and a non-serving cell-defining SSB(e.g., serving and non-serving cell-defining SSBs being transmitted fromthe same TRP), a UE may assume that contention-based random access isallowed for a dedicated RACH configuration associated with thenon-serving cell-defining SSB and may select one of the RACHconfigurations (e.g., cell-specific or UE-specific) depending on theRACH use cases (e.g., scheduling priority or QoS requirements of arrivedUL data). In such embodiments, if quasi-co-location (e.g., between theserving and non-serving cell-defining SSBs) is not indicated butallowance of contention-based random access on the dedicated RACHconfiguration is indicated (e.g., this may be if one or more RACHpreambles sent from a UE according to the dedicated RACH configurationare monitored only by a TRP transmitting the non-serving cell-definingSSB), the UE may choose one of the RACH configurations (e.g.,cell-specific or UE-specific) based on a combination of RACHconfigurations and required preamble transmit power (and/or estimated DLpath loss). In one embodiment, if quasi-co-location (e.g., betweenserving and non-serving cell-defining SSBs) is not indicated but CBRA isallowed on a dedicated RACH configuration, a UE may obtain a DL timingand a DL path loss estimate based on an indicated DL path loss referenceSSB and/or DL signal associated with the dedicated RACH configuration.In certain embodiments, if a UE does not receive an indication relatedto quasi-co-location and does not receive an indication related toallowance of contention-based random access but does receive anindication that a timing, a frequency, and/or a DL path loss referenceSSB and/or DL signal for a dedicated RACH configuration is a non-servingcell-defining SSB, the UE may assume that contention-based random accessis allowed for the dedicated RACH configuration.

In various embodiments, RMSI may include all RACH configurationsassociated with all cell-defining SSBs of a wideband carrier, and/orother system information may include all of the RACH configurationsassociated with all of the non-serving cell-defining SSBs of thewideband carrier. In such embodiments, all of the cell-defining SSBs ofthe wideband carrier may be transmitted from one TRP, and correspondingRACH resources may be monitored by one TRP (e.g., the same TRP). In oneembodiment, a UE uses a RACH configuration of a serving cell-definingSSB for initial access (e.g., initial cell selection). In such anembodiment, once connected, the UE may perform contention-based randomaccess on a RACH configuration of any cell-defining SSB of the widebandcarrier. In certain embodiments, each RACH configuration may havedifferent values for some parameters (e.g., a preamble power rampingstep size, an initial value of a backoff parameter, etc.) for differentRACH prioritization depending on a RACH configuration.

In certain embodiments, RMSI or OSI may include RACH configurationsassociated with a subset of cell-defining SSBs of a wideband carrier. Insuch embodiments, RACH configurations associated with remainingcell-defining SSBs of the wideband carrier may be configured to be UEspecific for connected mode UEs.

In one embodiment, a UE may change a serving cell-defining SSB byreceiving an indication on a change of a default DL BWP. In suchembodiments, the serving cell-defining SSB may be transmitted in adefault DL BWP. Moreover, a gNB may command or indicate to the UE tochange the serving cell-defining SSB without interrupting on-going datacommunications by transmitting reconfiguration signaling relating to thedefault DL BWP. In such embodiments, the reconfiguration signalingrelating to the default DL BWP may include a PCID and a synchronizationsignal frequency location of a target cell-defining SSB. Furthermore, insuch embodiments, if the reconfiguration signaling relating to thedefault DL BWP does not include information on the target cell-definingSSB, a UE may assume that the serving cell-defining SSB is not changed.

In various embodiments, if one or more cell-defining SSBs (e.g., a firstSSB, a second SSB, and/or a third SSB) on different synchronizationsignal frequencies within a wideband carrier are transmitted by one ormore cooperating TRPs (e.g., a first TPR, a second TPR, and/or a thirdTRP) which may be connected to a common central processing unit or basestation, a gNB may change a serving cell-defining SSB of a UE among theone or more cell-defining SSBs of the wideband carrier by reconfiguringthe default bandwidth part of the UE.

FIG. 4 is a schematic block diagram illustrating one embodiment of asystem 400 including multiple TRPs. The TRPs may be connected to acommon central processing unit or base station. The system 400 includesa first TRP 402 that may transmit a first SSB, a second TRP 404 that maytransmit a second SSB, and a third TRP 406 that may transmit a thirdSSB. The system 400 also includes a first UE 408 that may receive thefirst SSB from the first TRP 402, a second UE 410 that may receive thesecond SSB from the second TRP 404, and a third UE 412 that may receivethe third SSB from the third TRP 406. In one embodiment, the second UE410 may move from the second TRP 404 toward the third TRP 406 asillustrated by arrow 414. Accordingly, the second UE 410 may need to betransitioned from using the second SSB to using the third SSB.

FIG. 5 is a schematic block diagram illustrating one embodiment of SSBtransmission in a system 500 having multiple TRPs. The system 500includes a first SSB 502 (e.g., the first SSB transmitted from the firstTRP 402 of FIG. 4 ), a second SSB 504 (e.g., the second SSB transmittedfrom the second TRP 404 of FIG. 4 ), and a third SSB 506 (e.g., thethird SSB transmitted from the third TRP 406 of FIG. 4 ) transmittedduring a time period 508 over a frequency range 510. While FIG. 5illustrates the first SSB 502, the second SSB 504, and the third SSB 506all transmitted in the same time period 508, in other embodiments, thefirst SSB 502, the second SSB 504, and/or the third SSB 506 may betransmitted in different time periods. Furthermore, as illustrated, thefirst SSB 502, the second SSB 504, and the third SSB 506 are alltransmitted in different frequency spans (e.g.., using different PRBs inthe frequency domain) within the frequency range 510.

FIG. 6 is a schematic block diagram illustrating one embodiment of SSBtransmission and PRACH resource configuration in a system 600 havingmultiple TRPs. The system 600 illustrates a first BWP 602 (e.g., aninitial and default BWP for the first UE 408 of FIG. 4 ). The first BWP602 may have, in one embodiment, a frequency span of 10 MHz and/or asubcarrier-spacing of 30 KHz. The system 600 also illustrates a secondBWP 604 (e.g., an initial active BWP for the second UE 410 of FIG. 4and/or a configured BWP for the first UE 408 of FIG. 4 ). The second BWP604 may have, in some embodiments, a frequency span of 20 MHz and/or asubcarrier-spacing of 60 KHz. The system 600 further illustrates a thirdBWP 606 (e.g., an initial and default BWP for the third UE 412 of FIG. 4and/or a default BWP for the second UE 410 of FIG. 4 ). The third BWP606 may have, in certain embodiments, a frequency span of 10 MHz and/ora subcarrier-spacing of 30 KHz.

The first BWP 602, the second BWP 604, and the third BWP 606 may includea DL slot 608 and an UL slot 610. In the DL slot 608 of the first BWP602, a first SSB 612 may be received by a UE. The first SSB 612 may be acell-defining SSB. Moreover, the first SSB 612 may have, in oneembodiment, a frequency span (e.g., bandwidth) of 7.2 MHz and/or asubcarrier-spacing of 30 KHz. In the UL slot 610 of the first BWP 602, afirst RACH resource 614 may be used for transmissions by the UE. Thefirst RACH resource 614 may be associated with the first SSB 612.Furthermore, the first RACH resource 614 may have a frequency span(e.g., bandwidth) of 1.08 MHz and/or a subcarrier-spacing of 1.25 KHz.

In the DL slot 608 of the second BWP 604, a second SSB 616 may bereceived by a UE. The second SSB 616 may be a cell-defining SSB.Moreover, the second SSB 616 may have, in one embodiment, a frequencyspan (e.g., bandwidth) of 7.2 MHz and/or a subcarrier-spacing of 30 KHz.In the UL slot 610 of the second BWP 604, a second RACH resource 618 maybe used for transmissions by the UE. The second RACH resource 618 may beassociated with the second SSB 616. Furthermore, the second RACHresource 618 may have a frequency span (e.g., bandwidth) of 8.64 MHzand/or a subcarrier-spacing of 60 KHz.

In the DL slot 608 of the third BWP 606, a third SSB 620 may be receivedby a UE. The third SSB 620 may be a cell-defining SSB. Moreover, thethird SSB 620 may have, in one embodiment, a frequency span (e.g.,bandwidth) of 7.2 MHz and/or a subcarrier-spacing of 30 KHz. In the ULslot 610 of the third BWP 606, a third RACH resource 622 may be used fortransmissions by the UE. The third RACH resource 622 may be associatedwith the third SSB 620. Furthermore, the third RACH resource 622 mayhave a frequency span (e.g., bandwidth) of 1.08 MHz and/or asubcarrier-spacing of 1.25 KHz. As may be appreciated, the frequencyspans and the subcarrier-spacings described in relation to FIG. 6 areexamples only and may be any suitable values.

Returning to FIG. 4 , after connection set-up, a default BWP of thefirst UE 408 and a default BWP of the third UE 412 may remain the sameas an initial active BWP of the first UE 408 and the third UE 412,respectively. However, for the second UE 410, as the second UE 410 movestoward the third TRP 406, the second UE 410 may receive a default BWPreconfiguration signaling that may include information relating to atarget cell-defining SSB (e.g., the third SSB 620 of FIG. 6 ) and thesecond UE 410 may change its serving cell-defining SSB from the secondSSB 616 of FIG. 6 to the third SSB 620 of FIG. 6 .

FIG. 7 is a flow chart diagram illustrating one embodiment of a method700 for random access channel configuration. In some embodiments, themethod 700 is performed by an apparatus, such as the remote unit 102. Incertain embodiments, the method 700 may be performed by a processorexecuting program code, for example, a microcontroller, amicroprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, orthe like.

The method 700 may include receiving 702 a first cell-definingsynchronization signal block on a carrier. In some embodiments, themethod 700 includes synchronizing 704 to the first cell-definingsynchronization signal block. In certain embodiments, the method 700includes receiving 706 a first system information message associatedwith a first serving cell of the first cell-defining synchronizationsignal block. In such embodiments, the first system information messageincludes a first random access channel configuration. In variousembodiments, the method 700 includes receiving 708 a bandwidth partconfiguration via a dedicated message from the first serving cell thatindicates a bandwidth part configured with a second random accesschannel configuration. In one embodiment, the method 700 includesperforming 710 random access according to the second random accesschannel configuration in the bandwidth part of the first serving cell.

In certain embodiments, the second random access channel configurationis associated with a second cell of a second cell-definingsynchronization signal block of the carrier. In some embodiments, thefirst cell-defining synchronization signal block is from a firsttransmission and reception point and the second cell-definingsynchronization signal block is from a second transmission and receptionpoint, and the first and second transmission and reception points: arepart of the same entity, are connected via a backhaul, are controlled bya common scheduling unit, or some combination thereof. In variousembodiments, the second cell is not a serving cell.

In one embodiment, the method 700 comprises receiving informationcorresponding to the second cell-defining synchronization signal block,wherein the information corresponding to the second cell-definingsynchronization signal block includes a physical cell identity and asynchronization signal frequency location of the second cell-definingsynchronization signal block. In certain embodiments, the method 700comprises: receiving an indication that indicates that the secondcell-defining synchronization signal block is associated with the secondrandom access channel configuration and that the first cell-definingsynchronization signal block is not quasi-collocated with the secondcell-defining synchronization signal block; determining a downlinktiming and a downlink path loss estimate based on the secondcell-defining synchronization signal block; and transmitting a randomaccess channel on a random access channel resource corresponding to thesecond random access channel configuration.

In some embodiments, the first system information message includes atleast a portion of the second random access channel configuration. Invarious embodiments, the first system information message includessystem information for a connection set-up but not included in a masterinformation block. In one embodiment, the first system informationmessage is received in at least a portion of the carrier on which thefirst cell-defining synchronization signal block is received.

In certain embodiments, a portion of the carrier on which the firstcell-defining synchronization signal block is received comprises a firstportion of the carrier and corresponds to a first default downlinkbandwidth part of the first serving cell. In some embodiments, themethod 700 comprises receiving an indication reconfiguring the firstdefault downlink bandwidth part to a second default bandwidth partassociated with a second portion of the carrier and a non-servingcell-defining synchronization signal block in the second portion of thecarrier. In various embodiments, the indication indicates to a remoteunit to reconfigure the non-serving cell-defining synchronization signalblock in the second portion of the carrier as a serving cell-definingsynchronization signal block.

In one embodiment, the method 700 comprises receiving a first indicationindicating that the second random access channel configuration isassociated with a non-serving cell-defining synchronization signal blockand allows contention-based random access. In certain embodiments, themethod 700 comprises receiving a second indication that indicateswhether the non-serving cell-defining synchronization signal block andthe first cell-defining synchronization signal block arequasi-collocated.

In some embodiments, the method 700 comprises, in response to notreceiving an indication that the second random access channelconfiguration allows contention-based random access, determining thatthe second random access channel configuration bars contention-basedrandom access and allows contention free random access on a randomaccess channel resource associated with the second random access channelconfiguration. In various embodiments, the second random access channelconfiguration is received in a second system information message of thefirst serving cell, and the second system information message includessystem information not essential for a connection set-up.

FIG. 8 is a flow chart diagram illustrating another embodiment of amethod 800 for random access channel configuration. In some embodiments,the method 800 is performed by an apparatus, such as the network unit104. In certain embodiments, the method 800 may be performed by aprocessor executing program code, for example, a microcontroller, amicroprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, orthe like.

The method 800 may include transmitting 802 a first cell-definingsynchronization signal block on a carrier. In some embodiments, themethod 800 includes transmitting 804 a first system information messageassociated with a first serving cell of the first cell-definingsynchronization signal block. In such embodiments, the first systeminformation message includes a first random access channelconfiguration. In certain embodiments, the method 800 includestransmitting 806 a bandwidth part configuration via a dedicated messagefrom the first serving cell that indicates a bandwidth part configuredwith a second random access channel configuration. In such embodiments,random access is performed according to the second random access channelconfiguration in the bandwidth part of the first serving cell.

In certain embodiments, the second random access channel configurationis associated with a second cell of a second cell-definingsynchronization signal block of the carrier. In some embodiments, thefirst cell-defining synchronization signal block is from a firsttransmission and reception point and the second cell-definingsynchronization signal block is from a second transmission and receptionpoint, and the first and second transmission and reception points: arepart of the same entity, are connected via a backhaul, are controlled bya common scheduling unit, or some combination thereof. In variousembodiments, the second cell is not a serving cell.

In one embodiment, the method 800 comprises transmitting informationcorresponding to the second cell-defining synchronization signal block,wherein the information corresponding to the second cell-definingsynchronization signal block includes a physical cell identity and asynchronization signal frequency location of the second cell-definingsynchronization signal block. In certain embodiments, the method 800comprises: transmitting an indication that indicates that the secondcell-defining synchronization signal block is associated with the secondrandom access channel configuration and that the first cell-definingsynchronization signal block is not quasi-collocated with the secondcell-defining synchronization signal block; and receiving a randomaccess channel on a random access channel resource corresponding to thesecond random access channel configuration. In some embodiments, thefirst system information message includes at least a portion of thesecond random access channel configuration.

In various embodiments, the first system information message includessystem information for a connection set-up but not included in a masterinformation block. In one embodiment, the first system informationmessage is transmitted in at least a portion of the carrier on which thefirst cell-defining synchronization signal block is transmitted. Incertain embodiments, a portion of the carrier on which the firstcell-defining synchronization signal block is transmitted comprises afirst portion of the carrier and corresponds to a first default downlinkbandwidth part of the first serving cell.

In some embodiments, the method 800 comprises transmitting an indicationreconfiguring the first default downlink bandwidth part to a seconddefault bandwidth part associated with a second portion of the carrierand a non-serving cell-defining synchronization signal block in thesecond portion of the carrier. In various embodiments, the indicationindicates to a remote unit to reconfigure the non-serving cell-definingsynchronization signal block in the second portion of the carrier as aserving cell-defining synchronization signal block. In one embodiment,the method 800 comprises transmitting a first indication indicating thatthe second random access channel configuration is associated with anon-serving cell-defining synchronization signal block and allowscontention-based random access.

In certain embodiments, the method 800 comprises transmitting a secondindication that indicates whether the non-serving cell-definingsynchronization signal block and the first cell-defining synchronizationsignal block are quasi-collocated. In some embodiments, the secondrandom access channel configuration is transmitted in a second systeminformation message of the first serving cell, and the second systeminformation message includes system information not essential for aconnection set-up.

In one embodiment, an apparatus for wireless communication, theapparatus comprises a processor and a memory coupled with the processor,the memory comprising instructions executable by the processor to causethe apparatus to receive a system information message associated with asynchronization signal block, wherein the system information messagecomprises a first random access channel configuration, receive a radioresource control message indicating a bandwidth part configurationcomprising a bandwidth part configured in accordance with a secondrandom access channel configuration, and perform a contention-freerandom access procedure on the bandwidth part and based on the secondrandom access channel configuration.

In certain embodiments, the instructions, to perform the contention-freerandom access procedure, are executable by the processor to cause theapparatus to perform the contention-free random access procedure on oneor more resources associated with the second random access channelconfiguration.

In some embodiments, the instructions are further executable by theprocessor to cause the apparatus to receive a master information blockassociated with a cell, wherein the system information message comprisesone or more parameters for accessing the cell, and wherein the one ormore parameters are absent in the master information block associatedwith the cell.

In one embodiment, the first random access channel configurationcomprises one or more parameters including preamble initial receivedtarget power and a preamble power ramping step size.

In certain embodiments, the first random access channel configuration isassociated with an initial uplink bandwidth part.

In some embodiments, the first random access channel configuration isassociated with a first cell, and wherein the second random accesschannel configuration is associated with a second cell different thanthe first cell.

In one embodiment, the synchronization signal block comprises acell-defining synchronization signal block.

In certain embodiments, the first random access channel configuration isdifferent than the second random access channel configuration.

In one embodiment, a method of wireless communication at a userequipment (UE), the method comprising: receiving a system informationmessage associated with a synchronization signal block, wherein thesystem information message comprises a first random access channelconfiguration; receiving a radio resource control message indicating abandwidth part configuration comprising a bandwidth part configured inaccordance with a second random access channel configuration; andperforming a contention-free random access procedure on the bandwidthpart and based on the second random access channel configuration.

In certain embodiments, performing the contention-free random accessprocedure comprises performing the contention-free random accessprocedure on one or more resources associated with the second randomaccess channel configuration.

In some embodiments, the method further comprises receiving a masterinformation block associated with a cell, wherein the system informationmessage comprises one or more parameters for accessing the cell, andwherein the one or more parameters are absent in the master informationblock associated with the cell.

In one embodiment, the first random access channel configurationcomprises one or more parameters including preamble initial receivedtarget power and a preamble power ramping step size.

In some embodiments, the first random access channel configuration isassociated with an initial uplink bandwidth part.

In certain embodiments, the first random access channel configuration isassociated with a first cell, and wherein the second random accesschannel configuration is associated with a second cell different thanthe first cell.

In one embodiment, the synchronization signal block comprises acell-defining synchronization signal block.

In certain embodiments, the first random access channel configuration isdifferent than the second random access channel configuration.

In one embodiment, an apparatus for wireless communication, theapparatus comprising: a processor; and a memory coupled with theprocessor, the memory comprising instructions executable by theprocessor to cause the apparatus to: transmit a system informationmessage associated with a synchronization signal block, wherein thesystem information message comprises a first random access channelconfiguration; transmit a radio resource control message indicating abandwidth part configuration comprising a bandwidth part configured inaccordance with a second random access channel configuration.

In certain embodiments, the system information message comprises one ormore parameters for accessing a cell, and wherein the one or moreparameters are absent in a master information block associated with thecell.

In some embodiments, the first random access channel configurationcomprises one or more parameters including preamble initial receivedtarget power and a preamble power ramping step size.

In one embodiment, the first random access channel configuration isassociated with an initial uplink bandwidth part.

Embodiments may be practiced in other specific forms. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

1. An apparatus for wireless communication, the apparatus comprising: aprocessor; and a memory coupled with the processor, the memorycomprising instructions executable by the processor to cause theapparatus to: receive a system information message associated with asynchronization signal block, wherein the system information messagecomprises a first random access channel configuration; receive a radioresource control message indicating a bandwidth part configurationcomprising a bandwidth part configured in accordance with a secondrandom access channel configuration; and perform a contention-freerandom access procedure on the bandwidth part and based on the secondrandom access channel configuration.
 2. The apparatus of claim 1,wherein the instructions, to perform the contention-free random accessprocedure, are executable by the processor to cause the apparatus to:perform the contention-free random access procedure on one or moreresources associated with the second random access channelconfiguration.
 3. The apparatus of claim 1, wherein the instructions arefurther executable by the processor to cause the apparatus to: receive amaster information block associated with a cell, wherein the systeminformation message comprises one or more parameters for accessing thecell, and wherein the one or more parameters are absent in the masterinformation block associated with the cell.
 4. The apparatus of claim 1,wherein the first random access channel configuration comprises one ormore parameters including preamble initial received target power and apreamble power ramping step size.
 5. The apparatus of claim 1, whereinthe first random access channel configuration is associated with aninitial uplink bandwidth part.
 6. The apparatus of claim 1, wherein thefirst random access channel configuration is associated with a firstcell, and wherein the second random access channel configuration isassociated with a second cell different than the first cell.
 7. Theapparatus of claim 1, wherein the synchronization signal block comprisesa cell-defining synchronization signal block.
 8. The apparatus of claim1, wherein the first random access channel configuration is differentthan the second random access channel configuration.
 9. A method ofwireless communication at a user equipment (UE), the method comprising:receiving a system information message associated with a synchronizationsignal block, wherein the system information message comprises a firstrandom access channel configuration; receiving a radio resource controlmessage indicating a bandwidth part configuration comprising a bandwidthpart configured in accordance with a second random access channelconfiguration; and performing a contention-free random access procedureon the bandwidth part and based on the second random access channelconfiguration.
 10. The method of claim 9, wherein performing thecontention-free random access procedure comprises: performing thecontention-free random access procedure on one or more resourcesassociated with the second random access channel configuration.
 11. Themethod of claim 9, further comprising: receiving a master informationblock associated with a cell, wherein the system information messagecomprises one or more parameters for accessing the cell, and wherein theone or more parameters are absent in the master information blockassociated with the cell.
 12. The method of claim 9, wherein the firstrandom access channel configuration comprises one or more parametersincluding preamble initial received target power and a preamble powerramping step size.
 13. The method of claim 9, wherein the first randomaccess channel configuration is associated with an initial uplinkbandwidth part.
 14. The method of claim 9, wherein the first randomaccess channel configuration is associated with a first cell, andwherein the second random access channel configuration is associatedwith a second cell different than the first cell.
 15. The method ofclaim 9, wherein the synchronization signal block comprises acell-defining synchronization signal block.
 16. The method of claim 9,wherein the first random access channel configuration is different thanthe second random access channel configuration.
 17. An apparatus forwireless communication, the apparatus comprising: a processor; and amemory coupled with the processor, the memory comprising instructionsexecutable by the processor to cause the apparatus to: transmit a systeminformation message associated with a synchronization signal block,wherein the system information message comprises a first random accesschannel configuration; transmit a radio resource control messageindicating a bandwidth part configuration comprising a bandwidth partconfigured in accordance with a second random access channelconfiguration.
 18. The apparatus of claim 17, wherein the systeminformation message comprises one or more parameters for accessing acell, and wherein the one or more parameters are absent in a masterinformation block associated with the cell.
 19. The apparatus of claim17, wherein the first random access channel configuration comprises oneor more parameters including preamble initial received target power anda preamble power ramping step size.
 20. The apparatus of claim 17,wherein the first random access channel configuration is associated withan initial uplink bandwidth part.